Shorono: You need to install OpenAL, I'm not 100% sure what site would be legitimate so I'm not linking any.
That is bollocks.
When a product is sold instead of being given away for free, it is the manufacturer's and distributor's responsibility to make sure that it works as advertised -- without the consumer having to hunt down spare parts, repair manuals and special tools to fix any flaws.
Here on GoG, that means that the program code needs to be overhauled and adjusted to the current operating systems, among other things by including all DLLs, add-ons, drivers or whatever is needed for the software to operate correctly. Failing to do so is bad enough; complaining, punishing or threatening users who provide solutions and link to the necessary tools would be ridiculous and an outrageous impertinence.
If developers, publishers and GoG have any brains between their ears, they should be happy and grateful when the user community, their paying customers, fix the problems that were their job to fix in the first place, doing their job for them.